Introduction
- For pancake or stacked die systems, in Blown film extrusion is a very useful manufacturing process for making plastic films. This process is very important for the flexible packaging industry, especially when it comes to protecting the product from aroma or moisture. These films become even more important. With the help of extrusion, barrier films are made that work to prevent all these
- If you want to make food packaging, pharmaceuticals, agriculture or high-performance films, then it becomes very important for you to know about extrusion dies. The extrusion die system decides to a large extent the quality, strength and number of layers of the film, so it becomes very important to select a good die. Whether you make a normal film or a barrier film, it becomes very important to select a good die. In this article, some important dies have been described that are very useful in making extrusion films nowadays.
Table of Contents
Pancake-Die vs. Stacked-Die
Pancake Die:
For easy understanding, I give an example for the pancake die system. Pancake die like make “Pancake.”
- Imagine you are making a pancake.
- You put the batter in a single pan and make a single layer of it.
- In a pancake, all the ingredients are mixed, and you get a single uniform layer.
- Pancake die also works in a similar way—molten plastic comes out together in a concentric circular flow and forms a single-layer film or limited multilayer film.
- Simple Design, Easy to Operate, Basic Multilayer Possible.
Stacked Die:
For easy understanding , i give a example of a stacked die
Stacked Die System like a make a “Burger “
- Now imagine you are making a burger.
You add separate layers—bottom bund, then patty, cheese, tomato, and on top of that another bund - Each layer is controlled separately; you can add more cheese or remove tomato if you want.
- Stacked die also works in the same way—separately stacked plates make multiple layers of molten plastic, in which each layer can be controlled separately.
- Complex Design, High-Precision Control, Advanced Multilayer Films Possible.
In other words, all pancake dies are based on the stacked die principle, but not all stacked dies are pancake dies.
Pancake die or stacked die for barrier film
- In blown film extrusion, barrier films are easily produced using pancake or stacked dies because different extruders are used for different materials. For example, if you want to produce a 5-layer barrier film, you can do so using this die.
- This die system combines several layers together, resulting in a high-performance film that prevents oxygen, moisture, or gases from penetrating.
This is a co-extrusion die in which multiple layers are put together to produce a high-quality film. Pancake or stacked die is generally used for barrier films because each layer in the film is made of a different material.
such as:
Barrier layer (EVOH, PA, etc.): Used to prevent gas or moisture.
Sealing layer (LLDPE, LDPE, etc.): Used to seal the film.
Tie layer: Helps to form a bond between two layers.
Each layer is fed from a different extruder and gets combined inside the die.
Example:
If you need a 5-layer barrier film, the structure in a pancake/stacked die system will look something like this:
Outer Layer (Protection): LDPE/LLDPE
Tie Layer—Tie Material
Barrier Layer: EVOH/PA
Tie Layer—Tie Material
Sealing Layer: LLDPE/LDPE
Advantages of the Pancake/Stacked Die System:
- Better Layer Control: The thickness and distribution of each layer can be precisely controlled.
- High Barrier Properties: Multiple layers improve barrier performance.
- Flexibility: Customized films can be made by combining different materials.
- Cost-Effective: It is very cost-effective as it reduces wastage and makes production efficient.
Conclusion:
The pancake or stacked die system is an advanced technique in blown film extrusion used to produce high-quality, multi-layer barrier films. This improves the performance, strength, and durability of the films, which is very important to the packaging industry.
- Do you want to read more about types of extrusion dies?
- Do you want to read more about blown film extrusion dies?
FAQ For Die System
What is Pancake/Stacked Die System?
This is a type of co-extrusion die system in which multiple layers of plastic materials are stacked to form a high-performance film. Each layer is made of a different material and is fed from a different extruder.
How many layers can be made in a pancake die system?
Typically 3 to 9 layers can be created in this system, but more layers are possible in advanced systems.
What materials make up the barrier layer in a pancake die system?
EVOH (Ethylene Vinyl Alcohol): For oxygen barrier.
PA (Nylon): For gas barrier.
PVDC: For high barrier properties.
In Stacked die /Pancake die is it possible to split layers .Meaning add more layres using the same nos of input extruders like ABA 2 extruders 3 layers,
Say with 3 extruders get 5 or 6 or more layers.